1. Field of the Invention
The invention is generally related to a system and method for delivering natural gas from a utility gas service to power generation equipment installed in or around a building.
2. Background
Office building tenants across the country are increasingly sensitive to the quality and reliability of their electric power. Most are dramatically expanding their investment in and reliance upon sophisticated computer and telecommunications equipment and networks that are increasingly vulnerable to grid-related power fluctuations and outages. To retain existing tenants and to attract new ones, office building owners need to establish a new standard of service that delivers power with reliability and quality that effectively addresses these growing concerns.
One approach for providing such a standard of service involves installing on-site power generation equipment. Such power generation equipment may include state-of-the-art, gas-fired, distributed generation units that produce reliable, high-quality, and environmentally-friendly power and supplemental thermal energy. Such systems can provide an efficient way for office property owners to provide the power, reliability, and quality that will keep their facilities state-of-the-art and a step ahead of their competition. One method for installing and operating such equipment in a manner that mutually benefits both the installer of the equipment and the building owner is described in commonly-owned, co-pending U.S. patent application Ser. No. 11/586,646, entitled “Method for Providing Energy to a Building Using Utility-Compatible Distributed Generation Equipment”, filed Oct. 26, 2006, the entirety of which is incorporated by reference herein.
Some power generation equipment operates on natural gas. When installing such equipment in an office building, several challenges arise. For example, gas-fired microturbines typically require natural gas to be supplied at some minimum volume of gas flow and some minimum level of gas pressure in order to operate. In some instances, the utility can provide the required volume of gas flow but cannot meet or maintain the required level of gas pressure. In other instances, although the utility can supply the required volume of gas flow and level of gas pressure, frictional loss associated with piping the gas from the utility interface to the power generation equipment can result in the gas being supplied to the equipment at less than the minimum pressure level.
Another challenge when installing on-site gas-fired power generation equipment is installing the requisite piping to deliver the natural gas between the utility gas service and the power generation equipment. For a variety of reasons, it is often desirable to use pipe having a relatively small diameter (e.g., a diameter of less than 4 inches) for this purpose. For example, the use of smaller pipe can substantially reduce installation costs as smaller pipe is less expensive and easier to install than larger pipe. Additionally, the building codes of some cities require that pipe above a certain diameter must be welded together during installation. In addition to being cost-prohibitive, such welding is time-consuming and generates unpleasant odors, which can be problematic when the building is already occupied by tenants.
Although the use of a smaller diameter pipe for the gas delivery line is desirable, it is also problematic in that it limits the volume of gas flow to the power generation equipment and increases frictional loss, which reduces gas pressure. As noted above, gas-fired microturbines typically require natural gas to be delivered at some minimum volume of gas flow and some minimum level of gas pressure in order to operate.
Finally, any natural gas delivery system installed in a multi-tenant building, such as an office building, will likely need to satisfy local building codes and stringent safety regulations and requirements. However, most commercially-available gas delivery systems, such as most commercially-available gas boosters, do not provide the requisite control system necessary to satisfy these codes, regulations and requirements.
What is needed then is a gas delivery system that is capable of delivering natural gas from a utility gas service to power generation equipment installed in or around a building in a manner that meets the minimum volume and pressure requirements of the power generation equipment. The desired gas delivery system should advantageously use pipe of a relatively small size for delivering gas to the power generation equipment, thereby substantially reducing installation costs and eliminating the need for a welded gas line. The desired gas delivery system should also provide a control system that facilitates close control over the gas flow and ensures compliance with local building codes and safety regulations and requirements.